Linux: When you need to drill down deep into your files and folders to find something stored in the depths of your Linux-based operating system, open-source search tool Beagle is your best friend.

This free search application is a lot like Mac OS X's Spotlight or Windows 7's system search tools. It indexes files, IM transcripts, emails, images, web pages, and more as you use them. Beagle searches by any keyword or metadata associated with a given file, from the song title in an MP3 to the sender's name in an email. The handy search app even scours external hard drives and removable media.

Beagle works on the GNOME or KDE desktop and requires a handful of software packages to run, including Mono and sqlite. You may not need to bother downloading and installing anything, however, because Beagle ships bundled with most major Linux distributions, including Debian, Ubuntu, and Fedora Core.